package com.hww.gateway.config;


import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.gateway.discovery.DiscoveryClientRouteDefinitionLocator;
import org.springframework.cloud.gateway.route.RouteDefinitionLocator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.cors.reactive.CorsUtils;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;


/**
 * description:
 *
 * @author wangpeng
 * @date 2019/01/02
 */
@Configuration
public class CorsConfig {

  //这里为支持的请求头，如果有自定义的header字段请自己添加（不知道为什么不能使用*）
  private static final String ALLOWED_HEADERS = "x-requested-with, authorization, Content-Type, Authorization, credential, X-XSRF-TOKEN,token,username,client";
  private static final String ALLOWED_METHODS = "*";
  private static final String ALLOWED_ORIGIN = "*";
  private static final String ALLOWED_Expose = "*";
  private static final String MAX_AGE = "18000L";

  @Bean
  public WebFilter corsFilter() {
    return (ServerWebExchange ctx, WebFilterChain chain) -> {
      ServerHttpRequest request = ctx.getRequest();
      if (CorsUtils.isCorsRequest(request)) {
        ServerHttpResponse response = ctx.getResponse();
        HttpHeaders headers = response.getHeaders();
        headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN);
        headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS);
        headers.add("Access-Control-Max-Age", MAX_AGE);
        headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS);
        headers.add("Access-Control-Expose-Headers", ALLOWED_Expose);
        headers.add("Access-Control-Allow-Credentials", "true");
        if (request.getMethod() == HttpMethod.OPTIONS) {
          response.setStatusCode(HttpStatus.OK);
          return Mono.empty();
        }
      }
      return chain.filter(ctx);
    };
  }
  /**
   *
   *如果使用了注册中心（如：Eureka），进行控制则需要增加如下配置
   */
  /*  @Bean
    public RouteDefinitionLocator discoveryClientRouteDefinitionLocator(DiscoveryClient discoveryClient) {
        return new DiscoveryClientRouteDefinitionLocator(discoveryClient);
    }*/
}
